Hannover 2016 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 46: Quantum Gases: Bosons V
Q 46.6: Talk
Thursday, March 3, 2016, 12:15–12:30, e001
Interacting bosons on two-leg ladders in magnetic fields — •Sebastian Greschner1, Marie Piraud2, Fabian Heidrich-Meisner2, Ulrich Schollwöck2, Ian McCulloch3, and Temo Vekua1 — 1Institut für Theoretische Physik, Leibniz Universität Hannover, Germany — 2Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München — 3ARC Centre, University of Queensland
Ultra-cold bosons in ladders with an externally applied synthetic magnetic field exhibit a surprisingly rich physics and a wealth of quantum phases for different interaction strengths. In the regime of hardcore repulsive bosons we observe Meissner and vortex liquid phases both in the superfluid and in the Mott insulator regime [1]. For the case of moderate and weak interaction strengths [2] we show how additionally for certain commensurate vortex-densities vortex-lattice phases form and a superfluid phase with spontaneously imbalanced particle number between the legs of the ladder, the so-called biased leg phase, emerges. The vortex-lattice phases with a spontaneously broken translational symmetry may exhibit a characteristic and counter-intuitive many-body feature: At sufficiently low temperatures for weak interactions strengths the edge current may reverse its direction.
[1] M. Piraud, et al., Phys. Rev. B 91, 140406(R), 2015.
[2] S. Greschner, et al., Phys. Rev. Lett. 115, 190402, 2015.